Again, as it had in Indianapolis just shy of a year ago, it fell short.

But yesterday, unlike that game against the Colts, the New England defense stood up and stared down the top-ranked offense in the NFL.

And the Patriots boarded their plane for the long flight home celebrating a 23-20 win.

As victories go, it certainly wasn’t pretty, but as any member of the Patriots would tell you, style points aren’t part of the NFL standings, and they say that New England is 5-1, tied with the Steelers and Jets for the league’s best record.

But back to that fourth-and-1 play.

On third and 3 from their 47 and clinging to a 23-20 lead, Tom Brady completed a screen to Wes Welker to his right, and Welker was knocked out of bounds near the first-down marker. Welker lost the ball and it was scooped up by Eric Weddle, who sprinted for the end zone, sending the Qualcomm Stadium crowd into a frenzy, but the officials ruled that Welker had been down by contact.

That crisis averted, coach Bill Belichick decided to challenge the spot of the ball, hoping to get the first down that way. Only referee Tony Corrente upheld the spot, and by losing the challenge the Patriots lost their last timeout.

Jim Davis/Globe Staff

The Patriots celebrated and the Chargers fretted as they watched the would-be game-tying field goal clang off the upright.

Yet Belichick did what he does: he went for it on fourth down, despite his defense having allowed the Chargers to get into the end zone on their previous two drives to close a 17-point lead to just 3.

The reward outweighed the risk.

“If you get the first down, the game is over,” Brady said matter-of-factly.

The Patriots lined up, and Brady handed the ball to BenJarvus Green-Ellis, who headed wide left rather than up the middle. He was met by Antwan Applewhite, who dropped him for a 1-yard loss.

“If we would have made it, we could have pretty much ended the game right there,” Belichick said. “They made a good play. Give them credit. They’ve got a good defense.”

Before San Diego took over, with half the field to cover and just under two minutes to work with, the Patriots defensive players - some of whom were on the field for that loss to the Colts last year, when Peyton Manning drove for the winning touchdown - gathered.

“We just came out and said, `Earn your paycheck,”’ said safety Brandon Meriweather. “We knew it was on us.”

The unit did its job, while also getting help from the Chargers, who had almost as much to do with their losing than the Patriots did.

San Diego got 12 yards on first down, a pass from Philip Rivers to Antonio Gates, getting to the New England 35. The next two plays were incomplete passes to Patrick Crayton. On third and 10, a situation Belichick noted early last week the Chargers excelled at, Rivers went back to Gates, and the big tight end was stopped after an 8-yard gain by rookie safety Sergio Brown, playing his first career game after being promoted from the practice squad the day before.

Kicker Kris Brown faced a manageable 45-yard field goal try. That is, until offensive lineman Louis Vasquez, in with the protection unit, was flagged for a false start. Now Brown’s kick was from 50 yards.

He hit the right upright. No good. Brady took a knee. Fingers came uncrossed, prayers were answered.

Jim Davis/Globe Staff

Tom Brady was held in check by the Chargers for much of the day.

Despite the memories of last year’s fourth-down call in Indianapolis, no one was questioning Belichick’s decision in a relaxed postgame locker room.

“Bill is always going to put us in a position to make the plays that we need to make. I never doubt him. I never will doubt him,” defensive lineman Vince Wilfork said. “With a first down we would have sealed it. That’s how I looked at it. We had confidence in the offense to go out and do it. Unfortunately, they didn’t pick the 1 yard up.

“At the same time, we had confidence that we were going to stop them and force them to try to make a field goal, which we did. They couldn’t do it. It was just one side taking care of each other. We have to play as a team. We lose as a team. We win as a team.”

If the Patriots offense carried the day in the Cincinnati and Buffalo wins and special teams sealed the victory in Miami, yesterday was definitely a victory for the defense, which is rapidly making strides and gaining confidence.

New England got four first-half turnovers on consecutive San Diego possessions, one of which was a poor play by a rookie, but as Patriots cornerback Devin McCourty noted, a turnover is a turnover.

Unfortunately for the D, the offense did not do much with the gifts it was given.

The first turnover was a fumble by Kris Wilson that gave the Patriots the ball at the Chargers’ 22 and led to New England’s first touchdown, a 1-yard pass to a wide-open Rob Gronkowski.

The second turnover came when rookie free agent Richard Goodman made a nice catch and left the ball on the grass after falling down. Problem? He had not been touched by a Patriot. New England’s James Sanders picked up the ball and was immediately tackled. But the offense went three-and-out.

Turnover No. 3 was when Rivers, under duress, tossed a swing pass out to fullback Jacob Hester. Hester didn’t make the catch, and initially Rob Ninkovich ran past the ball. But the Patriots’ bench, realizing it may have been a backward pass, started yelling at him to get it. Ninkovich did, then ran with it until Rivers tackled him 8 yards short of the end zone.

San Diego challenged the call, but the ruling stood. New England managed negative-14 yards on the possession thanks to back-to-back sacks, settling for a Stephen Gostkowski field goal.

McCourty pulled in his first interception of the season for the fourth turnover, but again the offense went three-and-out.

The Patriots entered the locker room with a 13-3 lead and a paltry 38 yards of total offense.

“What offense?” Brady said when asked about his unit’s play in the opening 30 minutes. “We had a hard time moving [the ball] at all. We couldn’t get into a rhythm. The second half was better, but I don’t think it was great by any stretch.”

The Patriots found success in the second half by switching to a no-huddle, finding the end zone on their first possession after the break and getting a field goal on their second. The scores put them up, 23-6, with 11:27 to play.

Still, New England didn’t fill up the stat sheet: it had just 179 yards of total offense, the first time since Jan. 2, 2000 against Baltimore that it had fewer than 200 yards and won.

San Diego made an offensive adjustment as well, with Rivers working almost exclusively out of the shotgun after he primarily had been under center for the first three quarters.

By getting running back Darren Sproles involved in the passing game as well, the Chargers scored twice in seven-plus minutes, recovering an onside kick in the process to deny the Patriots a possession.

But the Patriots made the plays they needed to, and got a little luck - and the Chargers’ lack of composure - for a hard-fought, if ugly, win.